APPARATUS USED IN THE TRACKING OF OBJECTS

• US 3,804,485 A
• Filed: 10/25/1972
• Issued: 04/16/1974
• Est. Priority Date: 10/27/1971
• Status: Expired due to Term

• Current Assignee: Graham Morley Clarke
• Original Assignee: Graham Morley Clarke
• Inventors: Clarke, Graham Morley
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Evans, F. L.
• Application Number:
  US05/300,567
• Time in Patent Office: 538 Days
• Field of Search: 350/6,7,285 250/23R 178/7.6
• US Class Current: 359/216.1
• CPC Class Codes: G01S 13/66 Radar-tracking systems; Analogous systems
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves

Abstract

Apparatus for tracking an object within a plane area in space comprises means for scanning the area in non-parallel directions with flat beams of optical radiation and detecting radiation reflected from any object in the plane. A single flat beam is produced by causing a near-parallel beam of radiation from a laser to diverge in one plane only towards a rotatable multifaceted drum. Parts of each facet are reflective of the radiation and rotation of the drum causes the beam to scan the plane area; the remainder of each facet is transmissive of the radiation and permits the beam transmitted to be diverted towards a further multifaceted drum on which a reflective part of a facet thereof is in the path of the diverted beam and causes the beam to scan the plane area in a different direction.

Claims

1. Apparatus for tracking an object within a plane area in space comprising a source of optical radiation, an optical system arranged to form the radiation from the source into a flat beam, movable reflector means including at least two multifaceted drums rotatable in synchronism with each other about their longitudinal axes, the axes being inclined at a finite angle to each other, a first of said drums being at least partly reflective of the radiation and so disposed in the path of the beam from the optical system that a part of the beam is reflected from the drum towards said plane area and scans over the area, as the drum rotates, in a direction transversely to the direction of greatest divergence of the beam at the plane, beam diverting means for diverting the part of the beam not reflected by the first drum towards the second drum, said second drum being so located as to reflect radiation incident thereon towards said plane area and to cause the beam to scan over the area transversely to the direction of greatest divergence of the beam at the plane, and a receiver system responsive to the irradiation of the object by the scanning beams and to the relationship between the time into the scan that the object is crossed by the beam reflected by the first drum and the time into the scan that the object is crossed by the beam reflected by the second drum to determine the position of the object in said plane.

2. Apparatus as claimed in claim 1 in which the source of radiation is a laser.

3. Apparatus as claimed in claim 1 in which the optical system comprises a cylindrical reflective surface in the path of the beam.

4. Apparatus as claimed in claim 1 in which the optical system comprises a cylindrical lens.

5. Apparatus as claimed in claim 1 in which the receiver of the optical radiation is remote from said plane area and is adapted to receive radiation reflected from an object in the plane area.

6. Apparatus as claimed in in claim 1 in which each facet of said first drum is partly reflective and partly transmissive of the optical radiation.

7. Apparatus as claimed in claim 6 in which a predetermined portion of each facet is fully reflective of the optical radiation and the remainder of each facet is fully transmissive of the optical radiation.

8. Apparatus as claimed in claim 7 in which the boundary between said fully reflective and said fully transmissive portions of each facet extends parallel to the longitudinal axis of the drum for the length of the facet.

9. Apparatus as claimed in claim 1 in which said first drum is hollow and contains on its axis of rotation the beam diverting means.

10. Apparatus as claimed in claim 1 in which the beam diverting means comprises a plane mirror inclined to the axis of rotation of the first drum at an angle intermediate said finite angle between the axes of rotation of the first and second drums.

11. Apparatus as claimed in claim 1 in which the axes of rotation of the first and second drums are in a plane parallel to the plane of said area.